BANGKOK — Facebook users who "share" or "like" content that insults the Thai monarchy are committing a crime, Minister of Information and Communication Technology Anudith Nakornthap said Tuesday.

The warning is the latest threat to freedom of expression in Thailand, where authorities have increasingly targeted websites that they claim threaten national security, especially those criticizing the monarchy.

Insulting a monarch is a crime known as lese majeste, and Thailand's laws against it are the most severe in the world. Even repeating the details of an alleged offense – such as on social media sites like Facebook – is illegal under the lese majeste law and the related Computer Crimes Act, "which says that spreading illegal content – either directly or indirectly – is a crime," Anudith said.

He said anyone who is accused could be prosecuted – even foreigners using the Internet outside Thailand.

"If a foreigner abroad clicks 'share' or clicks 'like,' then the Thai law has no jurisdiction over that, but if there is a lawsuit filed and that person then comes into Thailand, then that person will be prosecuted," Anudith told The Associated Press.

Lese majeste arrests and convictions in Thailand spike during times of instability, when the law is used by political rivals to harass opponents. The current crackdown also reflects growing concern over the king's health and the future of an institution that has long united the country.

Statistics obtained by The Associated Press from the Office of the Attorney General show 36 lese majeste cases were sent for prosecution in 2010, compared to 18 in 2005 and just one in 2000.

Last Wednesday, Thailand's criminal court sentenced Amphon Tangnoppakul, a 61-year-old grandfather, to 20 years in prison for sending mobile phone text messages to a personal secretary of then-Prime Minister Abhisit Vejjajiva that were deemed offensive to the queen.

On Dec. 8, the court will deliver the sentence of Joe Gordon, a Thai-born American who has been held since May for translating excerpts of a locally banned biography of King Bhumibol Adulyadej and posting them online. Gordon pleaded guilty to the alleged crimes committed years ago while living in the U.S. state of Colorado. The case has raised concerns about the reach of Thai law and how it is applied to both Thai nationals and foreign visitors.

Meanwhile, the opposition Democrat party claims the government is not doing enough to protect the monarchy from being tarnished.

On her own Facebook page, Mallika Boonmeetrakool, deputy spokeswoman for the Democrats, pointed to YouTube and Facebook, in particular, for "bad outbreaks" of offensive content in recent months, and pressed the Thai government to ask the U.S. government and service providers to block such content.

"We should talk to the various Web operators, and if they don't cooperate, we should force them to and ban them," Mallika told AP. "The royal institution is the institution of our nation... There should be freedom of expression, but it has to follow the rules because we have laws that cannot be violated."

Critics worry that recent admonitions may be misinterpreted and that Web users may not know they are committing crimes.

"You have to understand that once you click 'like' on your wall, it will show up in your friends' feeds that you clicked 'like.' It can be considered as indirectly publishing that page," said Chiranuch Premchaiporn, executive director of independent news website Prachatai.com who faces 20 years in prison herself for failing to remove allegedly offensive online reader comments quickly enough.

The drumbeat of warnings has caused many to reconsider what they say online.

"I actually decided to stop being so openly critical or openly vocal on the issue, even on my personal Facebook page," said a law student and social activist, who became particularly nervous when online vigilante groups began scouring Facebook pages for lese majeste material and sending screen grabs to authorities. She spoke on condition of anonymity for fear that authorities would come after her.